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1: Re: Just got ST70 and have some questions....... (8.23)
Posted by apaya on 2003-11-15, 21:45:52 (65.70.186.172)
If you like the ST70 and want more power try the Dyna MKIIIs. They're even nicer than the ST70. Armin .......
2: Using 5U4 in an ST70 (8.23)
Posted by Father John on 2003-05-31, 15:21:11 (61.9.0.98)
The original ST70 came with the 5AR4 tube rectifiers. I was wondering if its possible to mod an ST70 that allows it to use the 5U4G tube ? is there an advantage of using the 5U4G in an ST70 ? Thanks. .......
3: ST70 with autobias/Class A (8.17)
Posted by iliemarg@yahoo.com on 2007-07-24, 06:31:53 (12.18.111.2)
Did somebody try to use ST70 in PP Class A? What result? What about ST70 with auto bias? Sound improving? Thanks, Ilie .......
4: ST70 Preamp (7.77)
Posted by John EH on 2002-11-15, 00:19:10 (210.254.151.98)
Charles, You could not have put it better. The ST70 is a dynamo not a dynaco given the right preamp. My nirvana comes from a Bottlehead Foreplay. It took me forever to get the right mix of tubes capac .......
5: Re: I've got one... (7.69)
Posted by E Winninger on 2000-08-25, 10:36:36 (128.210.251.11)
> General info, specifics, pictures. I guess Im just used to the volumes that have been written on the ST70. By comparison to the ST70 there is practicly nothing out there on the Cit. V. I do think m .......
6: The Truth is Written Here (7.69)
Posted by Steve O on 2002-07-25, 12:44:02 (198.208.223.35)
I just love it when people speak of ST70 upgrades that are really total circuit redesigns. Philosophically speaking, these are nothing more (or less) than some foreign amp on an ST70 chassis. Shades o .......
7: How do I run two ST70's or should I bother? (7.65)
Posted by Darn on 2002-06-06, 20:15:13 (198.81.16.33)
I picked up another ST70 so I thought hey, why not hook them both up. what are the pros and cons of running two mono ST70's? I am not sure how to do it, do I plug the second one into output 2 on my CJ .......
8: Re: Strapping ST70 for center channel H/T amp (7.59)
Posted by sj701 on 2002-02-20, 10:27:05 (208.21.98.2)
Can't you just parallel a ST70 input jacks and the output terminals one higher than your speaker ohm rating? I thought the ST70 manual showed this was the method to make it a pseudo mono block. Steve .......
9: Re: scott 299d versus Dynaco st70 (7.48)
Posted by EdT on 2004-05-26, 08:13:42 (192.18.43.10)
I can offer some opinions on 299a vs st70 how 'bout 299a vs st70? While both have classic tube sound, the 299a sounds lighter, faster, more neutrual and transparent. .......
10: Best ST70 mods??? (7.39)
Posted by Mitch N. on 2000-02-12, 12:58:13 (63.24.83.205)
Which Dynaco ST70 mods are the best? Whos replcement board is the best one? How does a modified ST70 stack up against some of the current (Big$$$) tube amps? I'm sorry because I know these questions h .......
11: Best ST70 kit (7.35)
Posted by 6SN7GT on 2004-11-12, 04:02:31 (65.0.238.240)
I've seen so many references to the ST70. What do inmates feel is the best ST70 kit, complete with good plans (buildability), and user-modifiable with better parts (or which comes with top of line par .......
12: Um... (7.32)
Posted by Steve K on 2002-05-06, 11:23:48 (24.247.204.147)
...I'd just like to take a moment to point out to everyone that Brian does not have a Dynaco ST70. As he points out, he has a ST70 Series II. The Series II was a re-badged SoundValves VTA70. It is a " .......
13: RE: I still much prefer the 6L6g in a dynaco st70 (7.31)
Posted by Michael Samra on 2010-12-31, 16:08:09 (98.64.193.181)
I love the 6L6g in the dyna st70 also. Bias the 6p3se at 45ma. If you have a stock ST70 bias circuit,bias it at 1.4v and that gets you pretty close. .......
14: Help, hum coming out of Dynaco ST70! (7.27)
Posted by Ron V on 2002-07-30, 20:05:02 (67.248.84.170)
I purchased a Dynaco ST70 for my daughter. While in my possesion, it worked fine. She took it to school with her, left it on one night and the thing began to hum. I know that there is plenty of info .......
15: Re: Curcio Dynaco st70 pc3 replacement board (7.24)
Posted by JJ Analog on 2002-07-18, 09:29:39 (130.20.128.81)
I think SoundValves or some other places have exact replacements for the ST70 board, as well as Curcio. Some folks strongly advocate keeping the 7199s in the ST70--search for some posts on this by Joe .......
16: RE: Triode Electronics ST70 vs. Auido by Van Alstine Ultravalve (7.19)
Posted by Paul Eizik on 2020-12-02, 11:36:09 (67.184.182.189)
I have a Dynakit ST70 that I installed the Triode Elec. driver board in some years back, but I can't comment on any of the many other ST70 boards and mods which I haven't heard. The Triode board gi .......
17: ST70 Quad Cap Sections/Lugs/Symbols (7.06)
Posted by vikeboy on 2002-02-28, 12:19:38 (205.238.199.77)
Thanks to all who have helped me so far in figuring this critter out. Since I don't have the 'pictorial diagram', I'm somewhat stuck on something, but please tell me if I have this right... On the Qua .......
18: RE: Dynaco ST-120?!!! Upscaled current issue ST70 from Bob Latino I believe (nt) (6.94)
Posted by Mick Wolfe on 2010-04-21, 19:43:53 (97.115.235.166)
Actually his ST70 is still featured right along with the ST120. Both are superb, but recently I've really been drawn to the ST70, especially when using the 6P3CE output tube.....pure magic. Thank you .......
19: ST70 questions: bias and hum problems (6.93)
Posted by Francis S on 2000-07-28, 06:16:21 (202.78.88.130)
Another ST70 just arrived. As I powered it up, I noticed an annoying hum which is completely gone when the amp is plugged to any preamp. I do not have this problem with another ST70 so I wonder what i .......
20: Re: What a chump I am! (6.92)
Posted by Eli Duttman on 2001-05-17, 02:12:54 (205.188.195.174)
No need to scrap the amp right away. The amp uses EL34s for finals, a matched quad of Svetlana EL34s or a matched quad of JJ (Tesla) E34Ls will take care of that. As for biasing, the amp is a "knock o .......
21: Pre amp for dynaco st70? (6.91)
Posted by HiFiOd on 2002-06-17, 11:18:44 (207.42.2.229)
WHat preamps match well with a stock st70? .......
22: Re: 5u4gb in Dyna ST70 (6.90)
Posted by Eli Duttman on 2002-02-14, 00:08:36 (152.163.194.201)
IMO, the substitution of a 5U4 for the 5AR4 in a ST70 is bad. Not only is the 5 V. winding overworked, but signal tube life is shortened, due to cathode stripping, too. If that's the only mod, the pow .......
23: Dynaco Stereo 70 / VAL VAA70 (6.88)
Posted by tentaclefiend on 2001-09-06, 19:06:10 (65.30.112.192)
I'm a bit new to mid/high end audio, so please correct me whenever I am wrong (or even a bit foolish). Anyways - I'm looking to buy either a ST70 or a VAA70 (if I can find one) and I'd like to know wh .......
24: RE: Dyna ST70 with Harbeth P3 (6.85)
Posted by airtime on 2020-08-16, 09:51:48 (24.251.225.215)
I'm using a ST70 with 85db speakers with no problems. .......
25: Re: Dynaco Kit (6.81)
Posted by John EH on 2004-03-28, 11:17:53 (68.66.228.217)
I've been eyeing this kit on eBay as well for the same price. I rebuilt a Dynaco ST70 not long ago and wish I'd have field stipped the unit and gotten it rechromed. Many is the day I'd like to disasse .......
26: Re: dynaco st70 vs st120 (6.78)
Posted by Dave V on 2000-03-24, 18:26:41 (152.163.197.189)
I had a new ST70 and PAS3X back in the late 60's. Speakers were Bozak 305 3 ways.I enjoyed this system for five years but I felt the lower bass was always a bit shy.Treble was not a complaint other th .......
27: Re: Newbie Questions... ST70 (6.78)
Posted by Tom Bavis on 2002-02-24, 14:23:36 (66.66.185.194)
have you been here yet? http://www.netaxs.com/~vkalia/st70-rebuild1.html .......
28: Re: scott 299d versus Dynaco st70 (6.76)
Posted by qguy on 2004-05-26, 18:11:30 (203.190.77.194)
funny.... I got the opposite results when I compared a 299D vs a St70 Series II scott 299d...slower, better bass compared to the ST70 Series II .......
29: Re: Repair or Replace? (6.74)
Posted by Eli Duttman on 2000-01-24, 12:47:12 (204.146.164.129)
I have not listened to a ST70 since the 1960s (no memory of it whatsoever). The Decware Zen uses modern high quality parts (very few of them) and triode connected SV83s (an EL84 variant) in its O/P po .......
30: Re: A tube newbie's first impression of the ST-70 (6.70)
Posted by RBP on 2004-09-02, 08:15:52 (68.228.25.63)
Congrats on resurrecting this piece! I find the ST70 to be a great introduction to "the tube" sound. The ST70 gets quite a bit 'right' in its presentation and one should caution upgrades, as they have .......
31: RE: ST70 with autobias/Class A (6.67)
Posted by Door Nail on 2007-07-24, 08:32:35 (70.23.188.148)
Years ago Sound Value did a remake of the ST70 with auto bias. .......
32: Re: ST70 with 807s (6.66)
Posted by wildtubes on 2000-10-07, 10:41:39 (129.37.166.61)
EL34s are used in the ST70 because they are easier to drive (pentodes) than beam power tetrodes. Any modification to change the output tube must take into account whether or not the driver circuit is .......
33: Re: Dyna ST70 SDS cap board help! (6.63)
Posted by Uncle Ned on 2002-01-24, 18:31:00 (199.179.160.65)
The ST70 SDS Labs board goes in the same place where the bias capacitors are located, so it was necessary to include the bias circuit on the ST70 board.I don't think there's enough room in the Mk3 to .......
34: RE: Which ST70 complete kit should I build? (6.62)
Posted by TnTn on 2009-02-27, 23:19:14 (208.127.133.6)
Too bad you are a beginner or I would recommend that you get a chassis and transformer sets and get the K&K ST70 board. I have many vintage amps (Mac, Eico, Fisher) and this modded ST70 beat them all. .......
35: RE: I eliminated the preamp on a EICO ST70 also better than original (6.62)
Posted by DAK on 2018-08-22, 13:12:09 (66.91.168.87)
Sure, these units are getting harder to find, so making them a better performer is a big plus. I dunno if you are familiar with the EICO ST70 but it has MASSIVE output trannys. Seriously, they are hug .......
36: GZ32 for Dynakit st70? (6.59)
Posted by Niky on 2001-03-23, 02:41:10 (203.124.1.177)
I have this Pope GZ32. Can I use this tube in my st70? Thank. .......
37: ST70 bias setting (6.59)
Posted by Darn on 2001-11-28, 22:52:28 (198.81.16.53)
I just tried some new tubes in my ST70 How often should the bias need to be set on this amp? .......
38: Re: Holy s...... The tubes are fine. (6.58)
Posted by Uncle Ned on 2000-01-07, 03:56:50 (199.179.160.39)
> OLD new stock GE 12ax7's in a ST70. I cannot believe these 1960 model >dyna-saurs. What 12ax7 would you choose? Ummm..what kinda mod is in your ST70 that it's got 12AX7's in it? > The General elect .......
39: Re: ST70 (6.58)
Posted by Gary Kaufman on 2001-11-19, 07:53:41 (65.96.206.132)
Bad solder joints or socket connections are the most common cause. Remember these where (mostly) kits and the soldering quality was highly variable. I've seen some very interesting miss-wirings and ev .......
40: Re: Can ST70 be made to run on 240v? (6.58)
Posted by lilolee on 2002-03-23, 15:41:40 (62.31.54.225)
I live in the UK and bought an ST70. I use a 1Kv stepdown transformer. Nothing exotic, just HUGE. It does the trick. Lee .......
41: Anyone use or hear Kennedy Tube Audio ST70 board (6.56)
Posted by Eric Winninger on 1999-12-14, 15:06:42 (204.48.23.149)
I'm researching ST70 driver boards. I was curious if any one is using or has listened to the replacement board for the ST70 from Kennedy Tube Audio? I think it uses one 12AX7 for driver and two 12AU7 .......
42: RE: SHUGUANG 5ar4/gz34 ANY GOOD? (6.55)
Posted by Palustris on 2009-08-17, 12:47:09 (76.118.146.246)
The 5AU4 requires a filament current of 3.75 amps! That is guaranteed to fry the power transformer of a ST70. I haven't checked a ST70 lately, but it is possible you could fit a 5V 4 amp filament tran .......
43: Dynaco ST-70 Power Transformer (6.50)
Posted by Paul on 2003-03-22, 11:02:28 (66.185.84.197)
Hi, I am just wondering how many version of original power transformers available for Dyaco ST70? I've seen some dyanco ST70 with a power transformer like it has been made by plastic and it's has been .......
44: RE: Gold lion reissues (6.44)
Posted by Tyson on 2009-03-03, 21:58:44 (206.81.73.146)
Yep, already got all the upgrades, including the PIO K40's. I got the 35 watt ST70, but I bought TWO of them. I'm actively tri-amping my VMPS RM40's, so I have a SS amp on the woofers, a ST70 on the m .......
45: Re: Dynaco ST-70 Kits?? (6.41)
Posted by pkeller on 2001-11-21, 23:04:55 (206.133.238.90)
I have an ST70 with the Triode Electronics board and another ST70 that has been rebuilt to stock specs with 1% metal film resistors. the resistors are of the same brand used in the Triode board. Th .......
46: Help: Replacement parts for Dynaco ST70... (6.41)
Posted by Drew on 1999-08-10, 18:41:20 (208.155.155.146)
I am in the process of rebuilding my Dynaco ST70. I need to know what capacitors and resistors to change to give better sound and bass response. Thanks .......
47: Re: Strapping ST70 for center channel H/T amp (6.39)
Posted by sj701 on 2002-02-21, 19:23:23 (205.188.200.56)
That makes sense. I've never tried strapping my ST70, now I know it probably isn't worth trying by the manuals method. Thanks Steve .......
48: Other Dynaco Kits (6.39)
Posted by Bunt on 2004-03-28, 11:13:10 (67.119.139.8)
Paul, Another Asylum Member sells kits for the ST70 and the ST35. I can't recall who, but I will give you a link to his site. He sells his kit for 660 with all the parts. You can buy all the parts sep .......
49: Re: Yes I do! (6.38)
Posted by maddog on 2001-01-25, 17:20:13 (150.135.117.16)
Thanks Glimmie, After looking at the spec numbers for the Hammond and other info passed on to me (i.e. the MkIV is one channel of the st70) it looks like the power transformer is the same as the st70 .......
50: A liitle out of my price range (6.37)
Posted by fin1bxn@msn.com on 2007-02-09, 09:51:35 (153.2.246.30)
Thanks but, I'm looking to see If I can better a upgraded ST70 for under $1000. I think the ST70 sound good as is and with a better board will be an outstanding amp, but for the sam money or a little .......
51: RE: which new production GZ34/5AR4 to buy? (6.36)
Posted by DannyR on 2012-06-05, 14:43:50 (24.143.240.235)
Jim, if you do the diodes in series trick is it safe to have 40uf or even 50uf right after the new stuff? Also which would you recommend for a Dynaco ST70 and Eico ST70? .......
52: Can I try KT88s and 6550s in this ST70 amp? (6.36)
Posted by vett93 on 2007-07-29, 21:39:24 (75.32.144.37)
Since I can adjust the bias current on this Dynaco ST70 amp, can I try other power tubes such as KT88, 6550, etc? .......
53: Re: Try the Welborne ST70 rebuild kit (6.35)
Posted by 4season on 2002-07-25, 12:22:26 (205.240.11.90)
I love this kit and think the price is silly-cheap: It keeps the things you liked about the ST70 and fixes the not-so-nice parts. Sonically, it's lively and engaging and has no particular vices. This .......
54: Why the ST70? (6.35)
Posted by dvb on 2004-07-29, 10:42:47 (24.67.253.203)
I don't want to upset your apple cart, but I am wondering what has made you choose the ST70 as a starting point? Do you think it will be a better match for the horns than, say, a 300B SET, or maybe a .......
55: improving the ST70's bass (6.31)
Posted by Francis S on 2000-08-26, 08:41:37 (202.78.88.130)
now 90% done with modifying my st70, and I must admit I'm very impressed with it's sound - sweet, romantic, simply musical. however, I can use some advice on how to tighten-up the bass a bit. thanks .......
56: Re: Dyna st70 Chassis finish (6.31)
Posted by Francis S on 2001-02-12, 23:40:39 (192.44.136.113)
If you are having the chassis re-chromed, do the same with the tranformers' end-bells. i'll post a picture soon on how my st70 transformed into a real handsome piece... .......
57: Re: Is 7591A really in production again? (nt) (6.31)
Posted by Uncle Ned on 2001-01-20, 15:59:12 (199.179.160.149)
No, you wouldn't have to rewire anything on an Eico ST40 (or anything else that uses 7591A's) to use the ElectroHarmonix 7591A. The only exception would be if someone had modified the amp to use 6L6's .......
58: dynaco st70 vs st120 (6.30)
Posted by jml on 2000-03-24, 06:56:22 (209.167.169.190)
Any thoughts about the sound of the st70 vs the st120 without doing any circuit upgrading. jml .......
59: Re: Need Tube Advice for ST70 (6.27)
Posted by tubeman on 2001-03-05, 23:11:24 (205.188.192.167)
Joseph, a friend,that works for ANTIQUE RADIO, recently loaned me a quad of JJ EL34s to try in my ST70. I was very suprised by the quality of sound that these tubes are able to make. My usual tube in .......
60: st70 7199"s (6.24)
Posted by Fredrixx on 2002-03-25, 17:11:42 (64.252.235.119)
my newley aquired st70 has "usa 7199" etches near the top. In a painted orange like color is "????co" with a line over. Are these original; any good? should I replace; Any suggested mods? .......
61: Re: JJ KT77s - Problems fixed? (6.23)
Posted by ojd on 2006-12-08, 13:50:17 (134.134.136.1)
I bought a matched quad from Eurotubes.com about 3 months ago for my ST70 and so far have had no problems. And BTW, these are the best sounding tubes I have ever heard in the ST70. .......
62: 6P3S-E help with Dynaco ST70 (6.23)
Posted by bhamham on 2009-10-02, 12:45:32 (77.101.128.233)
Can you guys help me make the changes I need to run the 6p3s-e please? I dropped them in but one started arcing blue light. Stock ST70 with the original board. Thanks for any help. Bruce ::: TOPIC: .......
63: For ST70 tweakers only: some questions for you... (6.23)
Posted by Francis S on 2000-06-08, 21:00:01 (192.44.136.113)
Hi there! My ST70 is now being shipped to me and I'm excited. Although this is not my only tube amp, this is my first vintage amp. I'm looking forward to getting the ST70 and really playing around wit .......
64: Eico ST70 (6.21)
Posted by Jim Lee on 2001-08-11, 07:06:56 (216.78.33.91)
Got a chance to purchase an Eico ST70. Don't know the condition or price. Is this a good amp, should I try to purhase it, and are parts available? Thanks, Jim .......
65: Re: What interconnects fit Dynaco ST-70? (6.20)
Posted by Eli Duttman on 2001-10-30, 09:36:22 (64.12.102.52)
If you want to use JR's 89259 cable with standard Dyna ST70 jacks, use the Neutrik NY852G RCA male on the ST70 end. Eli D. .......
66: svet EL34 vs JJ E34L in dynaco st70 (6.19)
Posted by Bulbo on 2002-07-12, 10:22:51 (148.165.74.140)
Hi, I own an st70 with JJ E34L tubes. What difference in sound can I expect by trying svetlana EL 34. Thanks .......
67: ST70 with VTA70 mod? (6.18)
Posted by hee on 2003-03-19, 17:21:04 (210.0.206.122)
I would like to know which mod package (VTA70) for ST70 changes the input tubes to 6U8A. Will a E80CF or even a ECF80 survive there? TIA. .......
68: Re: ST70 pops powering down: will it hurt my speakers? (6.18)
Posted by Bruce from DC on 2001-03-12, 14:24:55 (207.91.86.2)
I owned a ST 70 years ago, and it never did that. I would say that's an abnormality that you should be concerned about. Certainly, if it's strong, there's the possiblity of tweeter damage. Are you sur .......
69: Subsituting 7199 in Dyanco ST70 (6.17)
Posted by Glenayre on 2001-02-17, 20:30:32 (24.115.164.212)
I have an original Dynaco ST70 but want to replace the 7199's in my amp with a pair of 6an8's (because its hard and expensive to get 7199's). Does anyone know what pin connections I have to make for t .......
70: RE: Which ST70 complete kit should I build? (6.17)
Posted by Mick Wolfe on 2009-02-26, 10:54:12 (166.89.225.243)
If your listening levels are in the mid-80 db range or less, you would be more than fine with the Latino ST70. If not, check out his 60 watt ST120 kit. .......
71: ST70 Power cord ground question.... (6.15)
Posted by Fishfood on 2002-02-26, 08:12:45 (208.187.17.70)
I just made an diy power cable for my Dynaco ST70. Where within the unit do I attach the ground wire? Or do I just leave it unattached? Thanks, you all have been so helpful. .......
72: Ponit to point soldering for Dyna ST70 (6.12)
Posted by Niky on 2001-03-29, 11:51:55 (203.124.1.183)
I am thinking of using point to point soldering instead of change a new pc board for my ST70. Is there any advantage? Thanks. .......
73: Can ST70 be made to run on 240v? (6.11)
Posted by Hawlsey on 2002-03-23, 06:47:13 (208.187.133.194)
Hi- I am currently selling a Dynaco ST70 and someone want to buy it and take it somewhere where the power is 240v. Can you convert the Dynaco to 240v? Is it easy? .......
74: That is difficult to answere........ (6.11)
Posted by Jimmy on 2006-03-04, 05:19:09 (64.91.48.19)
'Ultimate Sound' & 'Full Potential' One could upgrade a ST70 to 6A5G triode tubes & a newer front-end board. That would sound real good, but is it really a ST70 after mods? .......
75: Re: ST70 : PCB components recommendations (6.11)
Posted by Bambi B on 2003-01-10, 20:12:17 (209.179.245.145)
Chris, It's not that this is a historic monument, but I have never heard an ST70 and thought I should hear it stock before deciding what made me unhappy. Also, I have never modified equipment before s .......
76: Unmatched 7199's in ST70 (6.10)
Posted by Hector on 2002-02-14, 13:11:32 (208.187.133.150)
I just picked up a Dynaco ST70 and was given two RCA NOS 7199's. But they don't have the same printing on the tube. The boxes are the same, although the numbers 7199 are printed differently. So these .......
77: Dyna ST70 Dating (6.09)
Posted by FredRixx on 2002-03-07, 20:09:40 (64.252.204.182)
From previous posts, The dynakit st70 were made from 1958 thru 1977. Question: How do I know what date mine was made? The big question? What mods are applicable to different dates? .......
78: Re: Weber Copper Cap for ST70 on the way. (6.09)
Posted by LikeWhatG? on 2004-01-11, 20:34:59 (24.94.126.237)
Awesome! I've been really curious about Weber's copper caps and how they'd do in an ST70. Please post your impressions or heck, at least shoot me an email about it!! Greg .......
79: ST70 by Hammond (6.09)
Posted by ojd on 2006-05-14, 18:02:39 (24.20.36.12)
I have seen several ST70 like amplifiers from Hammond organs on Ebay from time to time. These are hard wired (no pcbs) and only have 8 ohms outputs. Does anybody know if these are any good for hi fi u .......
80: amp bias help needed (6.09)
Posted by dst on 2000-01-02, 15:17:16 (152.163.194.186)
got a board for a dynast70 series II which I am running with iron from and original ST70. sounds very good but the bias system in the st70 series II -- 2 LEDs between a pot on each channel -- is not q .......
81: Dyna ST70 I/O jack replacement (6.06)
Posted by Ben on 2000-01-29, 10:24:53 (204.212.154.169)
Folks, I come to you again for help... I bought the AVA input/output jack replacement kit. My ST70 is all torn apart on the table. The trouble is that the old boards holding on the jacks were riveted .......
82: ST70 with 807s (6.03)
Posted by Carl Michaels on 2000-10-07, 10:27:08 (24.66.56.208)
This has undoubtedly been discussed before, but is anyone out there aware of a ST70 modification that employs 807s (or 6L6s)? I'm aware of Audio Research's ST-70-C3 mod (6L6GCs). I'm hoping for someth .......
83: Re: Best ST70 kit (6.03)
Posted by bluelobster on 2004-11-12, 07:44:50 (68.80.83.246)
If your talking about the Dynaco st70, these haven't been available for quite a long time. If your looking to restore one a search in this or the vintage forum will yield much info. A look into the "D .......
84: Phew! (6.03)
Posted by efhjr on 2003-01-13, 11:58:32 (65.105.28.216)
Well, I've removed the ST70 from my system (my Maggies are being powered only by my two McIntosh MC30s now, so it ain't so bad...). I figure it's time to keep the ST70 turned off before it gets any wo .......
85: Re: Sound Valves PC-3A driver board recommended for ST70? (nt) (6.02)
Posted by Francis S on 2000-06-07, 18:55:18 (192.44.136.113)
Have you heard the board and compared this with the stock board? I have not heard it myslf but 2 owners claim it retains the original "ST70 sound"...net, probably not an upgrade but a good reliable bo .......
86: Dynaco St70 Mono/Stereo Bypass (6.01)
Posted by Fishfood on 2002-02-06, 18:18:22 (208.187.133.163)
Could someone describe for me the best way to bypass the mono/stereo switch on the ST70. It seems like a good first project for my amp.... Thanks. .......
87: Self balancing paraphase inverter for st70 (6.01)
Posted by Fredrixx on 2002-03-28, 18:06:51 (204.60.248.195)
Is there a self balancing paraphase inverter mod for the dynakit st70. or do I have to create my own. Is there an equal circuit somthing similar??? .......
88: Re: didn't like the triode mod on my ST70 (6.01)
Posted by Gary Kaufman on 2000-08-12, 21:31:46 (24.218.120.46)
Put me down on the list of those who have tried this modification and never liked it. I have even "A-B'd" the sound between two otherwise identical ST70's. There is a thorough discussion of triode con .......
89: RE: EL34 vs KT-77 (6.00)
Posted by Mick Wolfe on 2015-09-14, 21:10:01 (24.251.111.11)
I went from the stock EL34's in my Latino ST70 to Genalex Gold Lion KT 88's. Have really enjoyed this tube over the years. I think Bob Latino originally liked the 88 in the ST70 as well, but I believe .......
90: Re: Dynaco ST-70 input impedance compatible with Mod. 3a? (6.00)
Posted by Steve O on 2002-12-10, 12:59:01 (198.208.223.35)
If stock, the ST70 has an input impedance of 470k ohm. Although a little higher than recommendations of preamp, there should be no problem in driving the ST70. .......
91: Solid State Vs. Tube Rectification (5.99)
Posted by dgrambo on 2000-03-02, 21:22:20 (207.217.13.80)
I'm shopping for Dynaco stuff (my first foray into glass) and I was curious as to the differences in sound. Any opinions? The items in question; MkIII's and ST70. I have options either way on either u .......
92: ST70 : PCB components recommendations (5.98)
Posted by Bambi B on 2003-01-10, 15:51:59 (216.244.1.52)
Mates, I recently purchased a reproduction blank PCB board for my Dynaco ST70. The board came with a layout but without exact values for resistors (1/2 or 1W) nor recomendations for components. It ap .......
93: Re: GZ32 for Dynakit st70? (5.97)
Posted by Gary Kaufman on 2001-03-23, 09:51:14 (155.41.71.43)
The GZ32 is really a 5V4G equivalent. Nice tube, but not a good choice for the ST70 - it won't handle the current well. Gary's Tube Page .......
94: Re: Pre amp for dynaco st70? (5.97)
Posted by John H on 2002-06-19, 02:35:10 (210.254.151.98)
I'm going to have to agree with the Foreplay from Bottlehead.com and the ST70 combination. That's my basic system and it sounds great. Both are simple circuits. Easy for a beginner to mod, and easy en .......
95: Re: Baojet EL34-4M int amplifier (5.96)
Posted by Don N on 2005-06-28, 15:09:56 (128.107.253.38)
Thanks Oscar, I will look into the tubes you recommend. By comparing this amp to my ST70 it should be 35W per channel. But since it is class A while ST70 is push/pull is the power per channel of this .......
96: Re: 5R4 Vs. 5AR4 (5.96)
Posted by Gary Kaufman on 2000-11-02, 12:30:33 (155.41.68.72)
The 5R4 is not a great choice for the ST70 - the B+ will be lower than desired and will sag significantly under load. Dynaco suggested the 5U4GB as a possible emergency substitution, but the 5AR4 is r .......
97: Coupling caps in Dynaco ST70 (5.95)
Posted by LikeWhatG? on 2003-01-17, 10:47:17 (24.161.240.231)
I've searched through these and other forums and am still unsure so I thought I'd try asking you folks. I've got an ST70 and I'd like to replace the coupling caps. Currently has Black Cats. I just don .......
98: Re: I've got one... (5.95)
Posted by Eric H on 2000-08-25, 10:48:38 (128.3.252.76)
Since you have one I guess you know the basics... I'm running JJ/Tesla 6L6GC's in mine. They have tall bottles and look great, but I've never run any other power tubes for sonic comparisons. I rebuilt .......
99: Dynacto ST70 to use EL38 (5.94)
Posted by JoeRB on 2008-11-09, 02:30:16 (219.78.98.179)
Hi, I have 4 pieces EL38 tube and I was told they can used to replace EL34 with proper bias. If EL38 were put in a Dynaco ST70, what adjustment do I have to make concerning the bias. Please enlighten .......
100: Re: any brands of tudes amp wth 30 watts and above with a price tag of below $800 (5.93)
Posted by Eli Duttman on 2000-06-07, 10:47:00 (204.146.164.129)
A used vintage Dyna ST70 (35 WPC) in decent condition should cost about $300. Check out EBay, Audiogon, and Audioshopper to buy a ST70. A used vintage Harmon-Kardon Citation II amp (60 WPC) should be .......
101: Best 30 watt tube amp under 1000 Used or new (5.93)
Posted by fin1bxn@msn.com on 2006-08-27, 06:54:42 (71.250.90.222)
I currently have a Dynaco st70 and have the itch to upgrade. I'm driving effecient speakers and have a Bottlehead foreplay preamp. I was looking at Mc - MC40's AES - AE25 Jolida - 302 Moding my ST70 L .......
102: VTV rebuild kit for ST70 (5.93)
Posted by TH2000 on 2000-04-06, 07:51:57 (203.151.39.11)
anyone used to buy rebuild kit for ST70 from VTV .......
103: Re: Newbie Dynaco ST-70 - Question about tubes (5.92)
Posted by Gary Kaufman on 2001-05-14, 10:23:39 (65.96.204.89)
Tristan - The ST70 schematic is on my web site below (as well as many other locations!). Tubes should be (2) 7199, (1) 5AR4 or GZ34 and (4) EL34 or 6CA7 if the ST70 is unmodified. Gary's Tube Page .......
104: Loundness modification for EICO ST70 (5.92)
Posted by nyindallas on 2008-07-31, 17:02:07 (74.196.122.43)
I have heard from a number of people that I will need to implement a LOUDNESS MODIFICATION for my soon to arrive EICO ST70. Does anyone have suggestions about where I can find ez to understand directi .......
105: Re: ST70 questions: bias and hum problems (5.92)
Posted by Gary Kaufman on 2000-07-28, 14:25:23 (24.218.120.46)
Chris is on the money - that will teach me to try and answer messages when I should be doing "real work"... Do check that the 15.6 ohm resistors haven't been swapped. I've seen lots of ST70's with oth .......
106: st70 pop (5.90)
Posted by jzadovsky on 2001-10-10, 12:57:39 (65.206.236.2)
10-10-01 I purchased a dynaco st70 amp some time back. I just completed recaping, wiring and improved filtering on the supply. Everything sounds good, except I get a popping sound from my speakers on .......
107: ST70 triode/NFB question (5.90)
Posted by Francis S on 2000-06-17, 16:21:53 (202.78.88.130)
Okay, the triode mod looks easy enough to do, but should I remove the NFB circuit as well. Has anyone removed the NFB from their ST70...and how is this done? Do I take out the 390mmf and 1K from the c .......
108: Re: Dynaco ST-70 restoration for dummies=) (5.89)
Posted by Fredrixx on 2002-07-23, 18:03:33 (64.252.237.161)
Research is the answer...Use the asylum serch for "st70" and more spicific topics as you learn. Also do outside meta-serches using "ixquick.com or metacrawler.com (or equal..there are lots more)...for .......
109: What's the scoop on Dynaco ST70 amp? (5.89)
Posted by gopher on 2000-01-22, 08:15:14 (216.214.28.205)
I am a newby on tube amps. I was talking to someone who recommended that I go with a used Dynaco ST70 amp that has been tweaked. Could someone fill me in on the history of this tube amp? .......
110: st70 bottom plate (5.88)
Posted by hifitommy on 2007-03-04, 07:57:35 (76.170.138.62)
admittedly i havent been doggedly searching but i need one. a friend worked on the st70 and somehow lost the bottom plate. i just wont fire it up that way (i guess i am nuts) and would like to find on .......
111: KT-66 i/o EL34 on a Dynaco ST70? (5.88)
Posted by Francis S on 2003-02-17, 11:47:43 (202.57.89.89)
Can I use the KT66 in place of the EL34 on the Dynaco ST70's? Do I have to adjust the bias voltage (1.56v with the EL34's)? Thanks, Francis .......
112: didn't like the triode mod on my ST70 (5.87)
Posted by Francis S on 2000-08-12, 19:01:12 (202.78.88.131)
Too laid back, uninvolving for my taste. I preferred the standard ultra-linear which has more presence. Everyone else seem to be recommending this mod here -- am I the only one who doesn't like this m .......
113: need help with Dyanco ST70 quad cap wiring (5.87)
Posted by Anton on 2002-12-11, 01:52:43 (24.67.253.203)
I have aquired a st70 amp that keeps blowing fuses, even after all the points to checks as told to me by the excellent folks on here. I find that the previous owner ran a wire from the #19 (driver boa .......
114: Replaceing ST70 resistors, what VDC rating? (5.87)
Posted by Eric Winninger on 2000-04-03, 06:19:18 (208.239.2.197)
I want to replace the old carbon resistors in my ST70. I was planing to use Holco. The Holcos are rated at 300 VDC is that enough to use in the driver circuits? How much voltage is on the various sect .......
115: For Koo... (5.87)
Posted by Father John on 2003-05-31, 17:32:36 (61.9.0.98)
Reason why I asked is because I've seen some ST70 in the past week sold @ ebay with the 5U4 tubes rather than the 5AR4 tubes. I said to myself, maybe I'm missing something here ??? anyhow, i currently .......
116: Need Tube Advice for ST70 (5.87)
Posted by joseph222 on 2001-03-05, 20:35:14 (64.217.12.42)
I am considering replacing all the tubes in my ST70 as an inital attempt to upgrade it's sound. They are not original tubes (some say radio shack). What would be some good recommendations (my budget i .......
117: Re: Suggestions for a cheap, easily sourced, but good GZ34.... (5.86)
Posted by ojd on 2005-06-20, 11:05:08 (192.55.52.4)
I have used the Sovtek GZ34 for a year now in my ST70, works fine with no signs of getter deterioration. Tested with my BK tube tester, could no tell the difference from a new one.It should be noted t .......
118: Cap failure or loose ground? (5.85)
Posted by steven oda on 2000-12-03, 22:56:38 (63.30.253.7)
Also, check for loose transformer plates (or worse yet, bad transformers). Here's one link, to get you started and the ST70 link also: 1.) http://www.netaxs.com/~vkalia/st70-rebuild3.html 2.) Dynaco .......
119: Hovland... (5.85)
Posted by Steve K on 2002-05-26, 16:35:25 (24.247.204.147)
I own a Hovland Sapphire, and feel it's the best amp I've heard. It's a real powerhouse of a 40wpc amp...lotsa balls! It is, however, $7800. If I were to buy an amp, and wanted to keep the cost under .......
120: Dyna st70 Chassis finish (5.84)
Posted by wskitche on 2001-02-12, 15:00:06 (130.74.220.79)
My st70 is a true rust-bucket, but i like the chrome finish. So, I was wondering if it is possible to attatch a wirebrush to a drill, scrub off all of the rust and remaining chrome, then clearcoat it, .......
121: Re: The Kimmel/Welborne circuit doesn't sound stock (5.84)
Posted by 4season on 2003-01-30, 20:29:47 (205.240.11.90)
Personally, I think it retains or improves every aspect of the ST70's sonics and greatly improves the ST70's groovosity. So while I definitely like it and would buy it myself, there's no way you're go .......
122: Re: Question Gary..? (5.84)
Posted by Gary Kaufman on 2001-02-16, 09:08:20 (155.41.71.43)
Although rated at 35 wpc, most ST70's seem to deliver more like 28-30 "honest" watts. I ran my Altec A-7's with an ST70 for a few days, but things had a habit of bouncing off of the shelves... I went .......
123: Dyna 70 - power transformer upgrades (5.82)
Posted by Josh Schultz on 2003-01-28, 13:06:10 (206.152.237.34)
I recently rebuilt my st70 with the original circuit with better quality passives (riken resistors, hovland coupling caps, replaced the quad cap with two high quality two-section Rubycon 47uf electrol .......
124: Stock ST70 Board and Heat Damage (5.80)
Posted by David A on 2000-03-10, 15:01:49 (128.97.52.236)
As a tangent to my post below on using paper in oil capacitors, I was wondering if anyone knows the effect on the sound of the ST70 of the darkening of the phenolic PCB around the 7199 driver tubes. D .......
125: Re: New vs. NOS --worth the $$$? (5.80)
Posted by Bambi B on 2003-01-16, 11:45:47 (209.179.246.186)
DLC, I have a very original ST70 that I am collecting components for. As I have never heard an ST70, I plan to get it into the best possible stock condition first. With power output tubes, I plan to u .......
126: Re: Sound Valves PC-3A driver board recommended for ST70? (nt) (5.79)
Posted by Francis S on 2000-06-08, 01:49:41 (192.44.136.113)
Thanks for the inputs... I guess as I newbie on the ST70, I'm a little confused on the various options without a point of reference on what that "original sound" is. In a few weeks I may be able to tr .......
127: Re: The 6L6 is such a great tube!!! I probably SHOULD just.... (5.78)
Posted by MIchael Samra on 2006-07-25, 21:32:55 (24.231.207.14)
I run 6L6gcs and KT66s in my dynaco st70 with the vta boards and they are such a marvel now that you have a circuit that can drive the tube.Bill Johnson did the same thing when he redesigned the st70 .......
128: Dyna ST70 Bias drop from 1.56v to .40v (5.78)
Posted by Niky on 2001-02-19, 03:36:27 (203.124.1.183)
Recently my ST70's bias(both channel)drop from 1.56v to .40v after playing for half to one an hour. Can anyone tell me what is the cause of the droping, will it damage the amp if I carry on using it? .......
129: Pre-amps choices for ST70 ? (5.78)
Posted by Father John on 2002-12-31, 05:59:30 (61.9.0.98)
Other than the most popular ST70 pre-amp choices like Foreplay, Pas 3 and Pas 4, any other preamps can this forum recommend ? OR are these the best matches for this amp ? Thanks... .......
130: Re: Opinions of Dyna ST-70 as Monoblocks???? (5.78)
Posted by Eli Duttman on 2000-07-13, 08:15:07 (204.146.164.129)
Using the switch on a ST70 to turn it into a monoblock does not work well at all. What is needed is to sum the voltage swings of the 2 sections. There was a thread on this subject recently. Search the .......
131: RE: Siemens EL-34 tubes (5.77)
Posted by geraldm121@hotmail.com on 2011-12-25, 13:23:22 (198.228.195.167)
I have a quad of Telefunken branded EL34's that Mike Samra identified as Siemens production. They are new in the box (I bought them in 1974 for a Dyna ST70 ) but I believe the plates are stapled, I'll .......
132: Re: RECOMMENDATION FOR EL34 & 12AX7 TUBES (5.77)
Posted by Tuneman on 2001-09-29, 12:08:01 (152.163.206.177)
Hey thanks, I will keep that in mind when I need tubes. I have not decided whether to get the Jolida JD202A, ST70, or build a kit. I heard the JD 302B and I thought it was a bit soft in the lower end, .......
133: ST70 Problem when turning on (5.76)
Posted by Fishfood on 2002-02-19, 07:56:02 (208.187.133.146)
When I first turn on my Dynaco ST70 and after letting it warm up, sometimes I get a very loud left channel and a very soft right channel. If I quickly turn on and of the power switch it evens out the .......
134: ST70: Safe to run with tubes in One Channel Only? (5.76)
Posted by vikeboy on 2004-02-09, 14:57:11 (68.82.196.102)
For trouble shooting purposes, would it be safe to run my Dyna ST70, with the left (or right) channel EL34 pair removed, but not both? TIA. ---VikeBoy .......
135: Re: Is this a battle I can't win...... (5.76)
Posted by isanut on 2002-03-06, 20:30:41 (65.29.24.151)
What do you want? I drive less efficient speakers with smaller amps than the st70, or the st70 strapped for triode (about 12 watts per channel) with great results. I even drive magneplanar mgIIIas wit .......
136: Buzzing Dynaco ST70 (5.75)
Posted by efhjr on 2003-01-03, 19:39:12 (66.25.80.82)
My trusty Dynaco ST70 recently began buzzing. All tubes are new, and the amp is bone stock. There is no buzzing in the sound output -- it's the chassis that seems to be buzzing. Perhaps it's time to r .......
137: Re: Need Tube Advice for ST70-7199s (5.72)
Posted by Dr Frugalle on 2001-03-07, 22:18:40 (209.179.248.172)
Friends, www.tubeworld.com shows a variety of NOs 7199s for twenty some dollars and up. (Disclaimer; I have never actually bought from this company) Someone gave me a ST70 recently so I have new world .......
138: ST70 Series II hummmmmmmmmmmm (5.70)
Posted by dst on 2000-12-03, 17:10:57 (205.188.192.51)
ST70 Series II board that runs off old Dynaco iron has started to hum through my speakers. Was never a problem in the past. Started low level hum, then got louder, now downright annoying. Thoughts? : .......
139: Re: Dynaco ST-70 Kits?? (5.70)
Posted by Francis S on 2001-11-21, 18:52:21 (202.8.224.133)
I have the Welborne Labs as well, and I agree with the comments of twystd. I have listened/auditioned at least 5 different ST70 boards excluding the stock and to my ears, Welborne is ahead in dynamics .......
140: .02 ceramic cap(s) in ST70 (5.70)
Posted by MitchN on 2000-05-04, 20:09:57 (63.11.218.153)
What is the .02 cap in my ST70? It looks to be a dual .02 ceramic cap. I broke one of the leads on mine and need to replace it. Can I just use two .02 caps? Are 1kv voltage sufficient? Thanks ::: TOPI .......
141: Re: Intro to Tubes 101 (5.70)
Posted by Thermionic on 2001-03-28, 19:11:12 (209.5.86.23)
For me there is no comparison. The Eico is far and away a better amp than the ST70, if you can operate with 20watts. You can get a little more (25w) with a little work. You should be able to find HF20 .......
142: Re: Dynaco's ST 70 and Mark 3 (5.69)
Posted by qguy on 2003-04-02, 18:45:07 (202.78.73.3)
okay now if theres not much difference between a 35 and 60 watt Monoblock (but a monoblock sure looks better to me...) I play pretty load so If I decide to use an st70 will there be a disadvantage/co .......
143: St70 - right channel in stereo mode not working (5.69)
Posted by Tking on 2000-09-09, 17:19:51 (141.155.127.101)
I recently hooked my Dynkit St70 back up. The right channel is blank in stereo mode. The tubes are all aglow. Anyone care to give me a differential diagnosis? I am not very astute at the innards of eq .......
144: Re: Help! Dynaco ST-70 tube glowing cherry red!! (5.69)
Posted by Gary Kaufman on 2000-11-04, 16:24:33 (24.218.120.21)
Most common cause in an unrestored ST70 would be a coupling cap (.1uf) going leaky. Swap the two EL34's on that channel and see if the problem follows the socket or the output tube. If it follows the .......
145: Voice of moderation, (5.68)
Posted by j rodney on 2004-09-01, 10:47:04 (128.231.88.6)
well, you mention the ST70 and looks what happens. Used to be the Heathkit W5 and Citation 5 would get a similiar waterfall of comments, but the W5's have fallen off of many radar screens and the Cita .......
146: Re: First tube DIY please advise (5.67)
Posted by wskitche on 2001-02-19, 02:23:15 (130.74.220.79)
I would have to agree with Alan on this, i just got an st70. It was a tad banged up, rusty and whatnot. But amazingly it came with new tubes and had no electrical problems. I have had a blast playing .......
147: Question About Van Altine ST70 I/O Jack Replacements (5.67)
Posted by vikeboy on 2002-06-20, 17:55:09 (205.238.199.87)
I'm thinking about replacing the input jacks and output terminals of my ST70 with the Van Alstine set. Supposedly the input Jacks are spaced further apart to allow for modern RCA plugs, without cuttin .......
148: RE: BTW, you seem to be knowledgeable of this problem so (5.63)
Posted by DannyR on 2017-11-25, 01:03:56 (74.51.153.109)
I completely agree. Any Dynaco ST70 based design etc really needs more than one 5AR4 to be at it's best or to go solid state recs with a voltage dropping resistor. I'd also bias the output tubes highe .......
149: Testing Dynaco ST70 Quad Cap Voltages? (5.62)
Posted by vikeboy on 2002-03-08, 19:08:31 (199.224.85.31)
Can someone explain, step by step, the safest way to test the voltages for each section of the ST70 quad cap? TIA. ---VikeBoy .......
150: Re: Jolida 302B vs. Dynaco ST-70 (5.62)
Posted by MIchael Samra on 2005-09-06, 13:15:10 (66.188.56.2)
Paully is correct in that you really have to mod a dyna st70 to compare it..The dynaco st70 is a 35 plus year old amp with old dated componets and the jolida of course is updated and much newer.What I .......
151: Headphones on a Dyna ST70? (5.60)
Posted by thoriated_tiger on 2001-10-30, 20:08:28 (208.63.229.153)
Howdy, fellow thorium addicts. Given a bone-stock Dyna ST70.. how would I go about adding a headphone jack to it? I'd like it to disconnect the speakers, while of course still showing a load to the pl .......
152: Re: check your email... (5.60)
Posted by BTW on 2005-07-04, 04:53:15 (203.120.68.71)
Hi Steve, If you have a schematics for the 7591 amp can you send it to me as well... I've a pair of Eico ST70 Irons lying around and I'm think of making a pair of monoblock 7591. I have the schematics .......
153: Re: Do all tube amps have 'laid back" bass???? (5.60)
Posted by Timbo in Oz on 2002-12-01, 17:04:33 (203.54.191.30)
the St70 may have dying filter/PSU caps. some of the upgrades improve on a standard ST70 in this area as well and it depends on the spkrs too. The bass from my two baby amps with big caps is great. ti .......
154: Re: What I did (5.60)
Posted by Jim Carlon on 2002-08-07, 17:08:54 (209.240.222.132)
I have a FP and am using it with a ST70, as suggested below, in an experimental system. I find myself listening to it much more than my 'A' system. With a FP/ST70 combination, new tubes and tweaks for .......
155: Re: Does anybody have specs on Dynaco MkIV Power Trannie? (5.59)
Posted by maddog on 2001-01-24, 16:30:18 (150.135.117.7)
Thanks for the reply. So do you think they just halved the current? Or possibly left off the second filament winding? If this is true, I wonder why they didn't just use a power tranny from the st70 fo .......
156: Gold Aero EL34 experience? (5.59)
Posted by Darn on 2001-10-17, 17:49:42 (198.81.16.187)
I purchased a set of Gold Aero E34L's today for my Dynaco ST70. Sixty bucks seemed like a good price for a matched quad. This will be the first set of tubes in my first ST70 so I have nothing to compa .......
157: Re: Modified ST-70 cap question (5.58)
Posted by Francis S on 2001-03-08, 13:12:49 (192.44.136.113)
i have the same board on my newly rebuilt st70 (see link below). my st70 sounds damn good with that board but this unit went through some major mods too. as you can see, i replaced the coupling caps t .......
158: Re: st 7 dynaco to audio research (5.57)
Posted by Brian on 2000-08-23, 12:32:23 (209.47.186.56)
If I understand what you are asking, you are looking to see if the Audio Research mod for the ST70 results in a D75/76 amp. The answer is definitely not. The designs are entirely different. I purchase .......
159: RE: Dyna ST70 with Harbeth P3 (5.56)
Posted by Mick Wolfe on 2020-08-17, 09:18:38 (72.211.145.99)
Are you allotting that $1200 for a modern build ST70 like a Latino or Van Alstine UltraValve? Considering you're thinking of spending $1200, I would certainly look at those options as well.(the UltraV .......
160: st70 output trans. becoming a paper weight (5.55)
Posted by Dave Z. on 2000-02-11, 17:50:49 (24.128.190.210)
I have a ST70 with a output trans. on the way out. My question to anyone is, what output trans. would replace it?, or what pair of output trans. should I look into to replace the both?? .......
161: Shunt volume pot mod on the ST70 (5.55)
Posted by Francis S on 2000-08-10, 09:46:56 (202.78.88.130)
Okay, I got curious - having read the easy-to-do and popular volume pot shunt mod on the Foreplay, I decided to install one on my ST70. (The ST70 amp runs direct to a CD player which has an output gai .......
162: Strapping ST70 for center channel H/T amp (5.55)
Posted by joe espo on 2002-02-19, 22:54:47 (63.52.96.7)
Can I strap a Dynaco ST70 to be used as a mono 70 watt amp to be used as my center channel for H/T. Why? Because I need to warm up the dialog on DVD. Don't know about everyone else but I find DVD cent .......
163: Re: I need opinions! Getting ready to take the tube plunge... (5.54)
Posted by Gary Kaufman on 2001-06-22, 10:01:41 (155.41.71.177)
The Dynaco St70 is a "rite of passage" as you enter the tube world. I'd suggest you go for it if the price is reasonable - around $250 US for a nice condition unit seems to be about the going rate, a .......
164: Re: Dynaco 70 transformer hum - bias? (5.54)
Posted by ojd on 2007-03-13, 03:56:26 (24.20.36.12)
ST70 power transformers are known for their mechanical hum, specially the older ones. One of the selling points of Triode Electronics ST70 replacement power transformers is that they "won't buzz & hum .......
165: Kennedy ST70 board (5.54)
Posted by David Anderson on 2001-09-17, 08:07:01 (63.198.134.175)
Hi, I was wondering if anyone has or knows where I could find a Kennedy Audio driver board for the ST70. Kevin doesn't have any more and doesn't know when or if they may become available again. I thou .......
166: Re: How do I run two ST70's or should I bother? (5.53)
Posted by mstamper on 2002-06-08, 12:48:23 (12.243.65.66)
I did exactly what the original poster wants to do. Following Dynaco's instructions, I wired each ST70 for mono. My understanding from Dynaco's documentation was that the bridged Stereo 70 was good fo .......
167: Eico ST70 opinions? (5.53)
Posted by stefan on 2000-09-03, 01:46:55 (62.224.244.166)
Hi everybody, someone here in Germany offers me an Eico ST70 for about 280,-$. Is this a good alternative for the ZenAmp, which would be my favourite concerning new gear? I am not very familiar with e .......
168: IT's ALIVE! AAAALLLLIIIIIIIIVE! (5.52)
Posted by thoriated_tiger on 2002-01-24, 17:54:41 (216.76.136.72)
Bwahahaha. Welp, from Ned himsself: the band in the ST70 cap board faces the front of the amp. I had it bassackwards and paid the price..one blown cap. The ST70 board takes care of bias rectification .......
169: RE: Dynakitparts.com (5.52)
Posted by ojd on 2007-10-16, 08:21:47 (134.134.136.1)
I bought their MKIII transformers, both output and power, their reproduction fiberglass MKIII pc boards, the ST70 input boards and several other parts. All have been of the highest quality and and wor .......
170: Re: Van Alstine Super 70i Upgrade. Good or Great??? (5.52)
Posted by Eli Duttman on 1999-08-31, 07:52:36 (204.146.164.129)
Check out the "Audio Basics" page RE: upgrading the ST70 at AVA's web site. There is a gold mine of information available. One key point that Frank VA makes is that everything done is within the limit .......
171: Installed VTA board in my ST70 (5.51)
Posted by fin1bxn@msn.com on 2007-03-01, 17:41:43 (71.250.135.139)
Purchased the vta board with the Auricap upgrade and Bam, the bass is tighter the viel is lifted. Its a new amp, very diferent from the stock st70. I like it. Can anyone tell me about break in time. I .......
172: Was just given a Dynaco ST70, what to do or who to have it restore for me? (5.51)
Posted by TubieNubie on 2012-10-11, 18:27:05 (174.103.237.122)
I was just given a Dynaco ST70 and PAS 3. They work, but obviously need attention due to age. Who can I have restore this? I know people say that its a good piece of kit to start out working on, but I .......
173: RE: VAC 90 EL34 tubes question. (5.51)
Posted by DannyR on 2017-02-03, 12:19:41 (74.51.153.109)
Looking at the measurements of a stock st70 done by Dave Gillispie the ST70 seems pretty linear unless some dc hits the inputs. Fix that and replace the gz34 with diodes plus a resistor to drop the vo .......
174: Sound Valves PC-3A driver board recommended for ST70? (nt) (5.50)
Posted by Francis S on 2000-06-06, 23:04:43 (192.44.136.113)
This board allows the use of 6GH8 instead of the 7199s and has upgraded parts that promises to restore the original sound but with higher reliability. Has anyone tried this? PC-3A driver board for t .......
175: 6GH8 vs 7199 (5.50)
Posted by rodney on 2003-05-07, 11:49:10 (137.187.78.202)
The original Dynaco ST70 and MkIV used 7199. The Sound Valves remakes of these amps, ST70 series II, Sound Valves VTA/70i and M-40 used 6GH8A's. If I remember right, they all used Phillips 6GH8A's. Th .......
176: VTA forum could help (5.50)
Posted by airtime on 2021-08-11, 07:17:08 (68.0.179.242)
There is a forum sponsored by VTA. You could go over there and ask what tubes are working out best with what ever model you end up with. I have the VTA ST70 that also has a broad choice of tubes. Just .......
177: Re: How do I run two ST70's or should I bother? (5.49)
Posted by Sector-7G on 2002-06-07, 13:29:24 (130.203.161.190)
If you really need the power, sell them and: 1. as others have suggested, buy say, Mk.III or maybe a bigger stereo amp, proceeds form two working ST-70's should put you into H-K Citation II teritory. .......
178: Re: Und zo it begins....questions for some appropriate choices for a tube newby (5.48)
Posted by Eli Duttman on 2001-06-18, 03:01:31 (205.188.200.172)
Your speakers are not efficient enough for use with 3.5 WPC BottleHead Paramour amps. A vintage Dyna ST70 which goes for about $300 will work. You will need a preamp for the ST70. The BottleHead Forep .......
179: ST70 feedback question (5.48)
Posted by MitchN on 2000-04-16, 08:56:33 (63.11.213.190)
Hello I have a ST70 that the previous owner cut off the 16 ohm output xfmr leads. I'm running the feedback from the 8 ohm outputs, which as I understand, gives me less feedback. I'm wondering what dif .......
180: EL34 tubes for Dyna ST70 (5.47)
Posted by msparks on 2008-07-13, 15:07:51 (24.5.150.237)
I have an modded Dyna ST70 and it is time for new EL34's. Does anyone have any thoughts on which tubes might produce the deepest bass? I use a passive pre-amp and need to rely on the amp for the bass. .......
181: dynaco st70 (5.46)
Posted by franco211 on 2002-09-26, 12:00:52 (24.191.66.225)
I am thinking of buying a dynaco st70 and completely rebuiling it. does anyone know approx how much it would cost for a complete rebuild. I want to rebuild to the origional spec maybe using better mod .......
182: Matched Tubes (5.46)
Posted by sj701 on 2008-01-29, 06:35:06 (63.87.72.50)
I have several amps and I am curious, how do I know if I need matched tubes in the output? For example I've been told I need matched pairs for my Dynaco St70 but not matched quads, due to the bias onl .......
183: Dyna ST70 one channel loud pops and no sound (5.46)
Posted by Niky on 2002-04-23, 11:46:37 (203.124.0.245)
When I turn on my ST70 after a few sec. there was a few "pops" came form the left channel and no sound from this channel after that. Then I turn off the main and interchange the 7199 tubes and turn on .......
184: ST70 Transformer Lams - what will I find... (5.45)
Posted by vikeboy on 2002-03-09, 06:11:24 (199.224.85.102)
I want to paint the end bells and the lamination 'edges' of my ST70's transformers separately, but have never removed end bells before. When I remove them, what should I expect? (I searched the archiv .......
185: RE: Which ST70 complete kit should I build? (5.43)
Posted by Skier on 2009-02-26, 06:01:23 (69.107.76.219)
My speakers are the B&W Naut. 805 bookshelf with an spl of 88 (I believe). A sterophile article says they measured these at 85 spl but that it is easy to drive. I think that rules out the st35. Do you .......
186: Stable replacement quartet / ST70 EL34 (5.42)
Posted by roberts@bandstand productions on 1999-12-19, 11:06:07 (208.149.44.219)
Since it has been years since shopping tubes , I want to retube a Dynaco ST70. Looking for a really stable quartet of EL34's. A long time ago Richardson ele. had nice tubes , any other recomendations? .......
187: 7199 to 6gh8 on original dynaco st70 board (5.42)
Posted by reddindian47@gmail.com on 2017-08-30, 04:52:54 (192.161.121.199)
Hi Guys and Girls. I am looking for a schematic to replace my worn out 7199 and convert it to 6gh8 on an original Dynaco st70 board. I have done this before a long time ago but I lost the schematic. P .......
188: Re: What's the scoop on Dynaco ST70 amp? (5.42)
Posted by Uncle Ned on 2000-01-22, 19:16:24 (199.179.160.174)
>I am a newby on tube amps. I was talking to someone who recommended that I >go with a used Dynaco ST70 amp that has been tweaked. Could someone fill >me in on the history of this tube amp? Introduced .......
189: Re: A little clarification... (5.42)
Posted by Bambi B on 2001-03-01, 19:04:17 (209.179.246.143)
Daveemac, A friend who is moving cross- country sent me his valve 1966 PAS 3 and ST70- and thoughtfully with the instruction manuals. The instruction manual for the ST70 says in the second paragraph o .......
190: Re: Jolida , any comments?? (5.42)
Posted by Tom §. on 1999-12-13, 06:51:54 (205.175.225.5)
You may want to look into the 102B or 202A. Although, you can get the 302B from Galen Carol for a shade over $800 after shipping expenses (the 102 and 202 are priced quite reasonably as well). I can't .......
191: Re: New 7199 board for st70 (5.39)
Posted by Gary Kaufman on 2001-02-14, 20:31:49 (24.218.120.21)
The originals clean up nicely as several have suggested. Don't just change parts, getting the gunk off of the board is essential to restoring an ST70. I use a chloronated solvent (Fedron) sold for cle .......
192: Yup.... (5.39)
Posted by M. Lucky on 2004-08-30, 09:31:13 (169.237.200.42)
I've got an ST70 feeding Forte IIs, and I've got no complaints. Trouble is, I don't have much to compare it to. Most of mt friends have only crap audio systems, and I've rarely ventured into the audio .......
193: Re: ST70 feedback question (5.37)
Posted by Uncle Ned on 2000-04-17, 21:52:33 (199.179.169.136)
You have an ST70 handy, you can answer this efffectively *using the speakers you have*, (as opposed to other people guessing, who don't know what you've got). Try it all three ways and hook it up to w .......
194: Re: Bottlehead Paramour (5.36)
Posted by LennyF on 2004-06-03, 17:49:17 (66.108.251.217)
I had a stock stero 70 for a few years. I now have a Paramour. If your speakers have a reasonable impedance curve and 'efficiency', and you're not looking to rock the house down, then there's simply n .......
195: Re: BTW, (5.35)
Posted by Eli Duttman on 2006-10-07, 18:57:06 (68.83.181.118)
The problem in replacing the power trafo is mechanical. I believe the unit uses a drop thru mount power trafo. Sourcing a replacement that will fit is going to be DIFFICULT. If we were dealing with a .......
196: Re: Dynaco ST70 II help (5.35)
Posted by josedouglas@yahoo.com on 2006-07-18, 06:54:15 (12.27.190.114)
Hi! I'm waiting on my new tubes to arrive to work on the bias (thinking on also setting it up so I can check bias manually); did find the coupling caps, thanks! I'll shop around for replacement... The .......
197: Re: I think that... (5.34)
Posted by Eli Duttman on 1999-09-01, 10:18:45 (204.146.164.129)
Alan Kimmel (the designer of the Welborne ST70 mod) put bandwidth limiting into his circuit too. You may very well be right that the AVA choices are a bit severe, however, the ideas of stopping core s .......
198: Just got ST70 and have some questions....... (5.34)
Posted by rwalton on 2003-11-15, 20:18:19 (12.89.186.41)
Hello All, I've now officially ventured into the tube world. Bought a very nicely refurbished ST70. It has the Curcio board that maintains the original driver circuit (7199 tubes) and the rest of the .......
199: Re: ASL Wave 8's/Klipsch Heresy II (5.33)
Posted by joseph222 on 2002-03-06, 14:41:18 (64.217.15.34)
I have used the wave-8's to drive my Heresy II's while my ST70 was being upgraded. In a moderate sized room (10X12), they have ample power (I could never go higher than about 2/3rds volume). They have .......
200: Re: Dynaco ST70 II help (5.33)
Posted by Nuke Em on 2006-07-17, 03:41:47 (65.118.130.130)
I have an ST70 II and it has been rock solid dependable. Are the output tubes chineese? that could be the problem. Mine came with E. German tubes but I tried chineese EL34's and they were garbage. Als .......
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